60a DC-to-DC Charger Powered by 220a Alternator

[otrfun]

Thinking about installing a 60a dc-to-dc charger in our truck camper. Have plans to power it with the 220a alternator in our truck. Under a worst case scenario it could load the alternator with an additional 60a load for several hours. Any chance whatsoever it could damage the alternator with this kind of load--especially if the truck's two batteries are also discharged and pulling maximum charge current at the same time?

Also have a question about how most DC-to-DC chargers operate. Is the DC-to-DC charger output voltage limited to the maximum available input voltage (produced by the alternator)? Or, can/will the DC-to-DC charger step-up the input voltage from, say, 13.9v to 14.4v if need be?

[theoldwizard1]

pianotuna wrote:
Hi,

Does anyone know if the V-10 has Battery Charge Protect?

From my research, Battery Charge Protect was only offered for a couple of years (pre 2012 ?) and only on F-Series SuperDuty.

This should not be confused with the "High Idle" option, which I think is still available, and used primarily with vehicles that have a PTO for things like hydraulic pumps.

My guess is that Ford dropped the option because the "smart charging" system actually did the job at no additional cost.

[deltabravo]

Also, a major wiring upgrade will be needed.

This is how I did it

[pianotuna]

Hi,

Does anyone know if the V-10 has Battery Charge Protect?

[otrfun]

theoldwizard1 wrote:

otrfun wrote:
Our plan is to accept whatever current we can safely and reliably get at an idle from our 220a alternator.

Nothing wrong with that as long as you do not need a partially discharge RV battery to be fully recharged by the time you reach your destination.

Without a DC-DC charger, that just will not happen.

Our plan is to accept whatever current we can safely and reliably get at an idle from our 220a alternator with a DC-to-DC charger.

[NRALIFR]

Here’s a link to the SVE Bulletin describing the Stationary Elevated Idle Control modes available on 2011 and later Superduties.

Note that this discusses PTO modes and BCP mode, and that BCP requires the use of a resistor between PTO REF and PTO RPM even though you aren’t using the PTO. My 2010 F450 didn’t require that resistor. BCP was enabled on it by simply giving the ECM a battery voltage reference on the BCP SW wire.

SVE BULLETIN Q-180R2

I can tell you from experience with this that the ECM manipulates the engine RPM much more aggressively when BCP mode is on. In fact, I’ve never noticed much change in the idle RPM when BCP is off.

Also, I seem to recall reading somewhere that BCP mode essentially integrated into the ECM the function that used to be handled by that gray box that you always saw on airport shuttles that were based on the Ford E series vans.

:):)

[theoldwizard1]

otrfun wrote:
Don't believe our Ram has anything equivalent to Ford's BCP.

The quick way to verify if you do or do not have that functionality built in, connect a voltmeter to the battery and start the engine. Leave the A/C and lights turned off. Check the voltage at the battery. It will probably be >14.0V. Let your vehicle idle for 5-10 minutes. Check the voltage. It will be close to 13.2V.

Now, turn on the A/C, fan on high and lights. The voltage at the battery will probably be higher and so will the idle speed.

otrfun wrote:
Our plan is to accept whatever current we can safely and reliably get at an idle from our 220a alternator.

Nothing wrong with that as long as you do not need a partially discharge RV battery to be fully recharged by the time you reach your destination.

Without a DC-DC charger, that just will not hgappen.

[theoldwizard1]

NRALIFR wrote:
On Ford superduties, there’s a feature called “Battery Charge Protect” that enables the ECM to monitor the battery voltage when the parking brake is set, and the transmission is in Park, and it will vary the engine RPM from 600-1200 while large power loads are on the charging system. This is for using inverters, DC-DC chargers, etc while idling the engine. The ECM also monitors the engine temperature while in this mode, and won’t let the engine overheat.

Admittedly, I am not intimately familiar with with the exact functionality of battery charging on all Ford products as I have been retired for over 10 years.

However, what you described is the basic functionality of all "smart charging" system. That is, to maintain a minimum battery voltage at about 13.2V. If this requires increased idles speed, then it will be increased.

[otrfun]

NRALIFR wrote:
otr, one thing you might look in to is whether there are any stationary power features that can be enabled on your truck that specifically pertain to managing the alternator output when idling.

On Ford superduties, there’s a feature called “Battery Charge Protect” that enables the ECM to monitor the battery voltage when the parking brake is set, and the transmission is in Park, and it will vary the engine RPM from 600-1200 while large power loads are on the charging system. This is for using inverters, DC-DC chargers, etc while idling the engine. The ECM also monitors the engine temperature while in this mode, and won’t let the engine overheat.

I have it enabled on my truck, and I use one of the up-fitter switches to turn it on. It does work, and I use it occasionally. It’s a little better than a high-idle tune on a programmer because it only does what’s necessary to maintain good battery voltage. But if your truck doesn’t have anything like that then I would look at getting a high-idle tuner if you intend to stationary charge using the truck. Doing that occasionally is your choice. Of course, if you need to do it a lot it may make more sense to buy a small generator. But, I try not to tell other people how to spend their money or use their equipment. As long as you’re paying your way, it’s your choice.

:):)

Don't believe our Ram has anything equivalent to Ford's BCP.

Our plan is to accept whatever current we can safely and reliably get at an idle from our 220a alternator. Hopefully, it's 60a. If not, we'll bite the bullet and go with a 50a or even a 40a if need be.

We look at a DC2DC charger as just another charge option. Not counting on it to do all our charging (also have a generator and some solar). However, on those occasions where the solar is not cutting it, and it's not possible to run the generator, it's nice to have a solid plan C.

[otrfun]

grizzzman wrote:
. . . Like a 300 horse engine is producing anything near that at idle......I have a 40 amp DC to DC charger. It is a buck-boost device. At 14 volts input will output 40 amps at 14.7 cost is 50 amps input. At 12.7 volts (gotta love "smart" charging) 34 amps at 14.2 volts. The 220 amp alt handled both at idle without issue.

Thanks, good to hear! You're the 2nd person that has successfully pulled 50a from their 220a alternator with their DC2DC charger. Even better to hear you were able to do it at an idle! We may just go with a 50a unit (vs. a 60a) just to play it safe.

[theoldwizard1]

Gdetrailer wrote:
Alternator IS NOT going to "call" for more "engine speed", alternator is extremely tiny "load", so small it is insignificant.

I am sorry but you are incorrect. Most (I always hesitate to say ALL) vehicle built after about 2000, have some type of "smart" charging system. The alternator DOES IN FACT "TALK" TO THE PCM and will ask for higher speed

Gdetrailer wrote:
If a 300HP engine cannot stand a 3.5 HP (1%) alternator load without the need to alter the RPM it is time to scrap that engine design, it is junk.

Your numbers are correct, except you have not accounted for losses (Second Law of Thermodynamics). At max output, it would not surprise me if a 220A alternator could consume around 20 hp !

Gdetrailer wrote:
Manufacturers do not even do that for the A/C compressor (RPMs DO drop when the A/C compressor turns on at idle, typically a 50 RPM drop in idle speed).

Hmmm ... seems to me that I ACTUALLY WROTE THE SOFTWARE that increased the idle speed of the engine at idle sometime back in the early 1980s !


Experience counts : 31 years of Powertrain Control System hardware and software.

[NRALIFR]

otr, one thing you might look in to is whether there are any stationary power features that can be enabled on your truck that specifically pertain to managing the alternator output when idling.

On Ford superduties, there’s a feature called “Battery Charge Protect” that enables the ECM to monitor the battery voltage when the parking brake is set, and the transmission is in Park, and it will vary the engine RPM from 600-1200 while large power loads are on the charging system. This is for using inverters, DC-DC chargers, etc while idling the engine. The ECM also monitors the engine temperature while in this mode, and won’t let the engine overheat.

I have it enabled on my truck, and I use one of the up-fitter switches to turn it on. It does work, and I use it occasionally. It’s a little better than a high-idle tune on a programmer because it only does what’s necessary to maintain good battery voltage. But if your truck doesn’t have anything like that then I would look at getting a high-idle tuner if you intend to stationary charge using the truck. Doing that occasionally is your choice. Of course, if you need to do it a lot it may make more sense to buy a small generator. But, I try not to tell other people how to spend their money or use their equipment. As long as you’re paying your way, it’s your choice.

:):)

[grizzzman]

Like a 300 horse engine is producing anything near that at idle......
I have a 40 amp DC to DC charger. It is a buck-boost device. At 14 volts input will output 40 amps at 14.7 cost is 50 amps input. At 12.7 volts (gotta love "smart" charging) 34 amps at 14.2 volts. The 220 amp alt handled both at idle without issue.

[pianotuna]

Hi,

It makes no sense to me to idle a 300 hp engine to end up with 3.5 hp of output. I don't think the diodes in the alternator will "like it", either.

[Gdetrailer]

theoldwizard1 wrote:

Define "heavy" ? If the typical vehicle load, at idle, is 40 A and you have an alternator capable of 100A, the alternator will just call for more engine speed. (Alternator don't reach max capacity until about 2000 engine RPM.)

Most trailer tow packages include a heavy duty alternator. If not, that is a good upgrade.

Alternator IS NOT going to "call" for more "engine speed", alternator is extremely tiny "load", so small it is insignificant..

Not sure how much HP you believe an alternator is going to need but 220A 12V alternator is 2,640 watts..

General rule is 746W is equivalent to 1 HP..

Using the general rule a 220A 12V alternator is going to need a max of 3.5 HP from an engine capable of 300+ HP which is about 1% of that engine..

If a 300HP engine cannot stand a 3.5 HP (1%) alternator load without the need to alter the RPM it is time to scrap that engine design, it is junk..

I think your assumptions that the body control or engine control is going to automatically "boost" the idle JUST FOR THE ALTERNATOR is wrong.

Manufacturers do not even do that for the A/C compressor (RPMs DO drop when the A/C compressor turns on at idle, typically a 50 RPM drop in idle speed).

Now if you are talking an "Ambulance or Emergency" prepped vehicle, that IS a different beast, those vehicles ARE modified and certified for those types of use where they may have special critical power needs..

[otrfun]

S Davis wrote:
I am running the 50 amp Redarc and everything has been working great. I am adding another pair of batteries and another 50 amp charger for 100amps total. I also have the snow plow prep on my 2019 Chevrolet with a 220amp alternator.

Thank you, S Davis!!! I was so hoping to hear from someone who had actually tried this. As I mentioned earlier, I also have a 220a alternator on my truck. Good to hear you had good results at 50a. It'll be interesting to hear how things go with 100a.

Do you primarily charge while you're on the road? Or, do you sometimes park and charge? If so, for how long? Are you able to obtain a full 50a while your truck is at a standard idle (vs. a fast idle)?